1. Field of Invention
This invention relates generally to pupilometers, and more particularly to hand-held pupilometers which, while suitable for general pupilometer test purposes, are particularly useful for "field" testing, i.e., testing at locations remote from an office, laboratory, or other building or controlled environment.
2. Prior Art
Modern pupilometers provide an indication of the state of an individual's autonomic nervous system by measuring the individual's pupillary response to a light stimulus. With such response data, it has been found that pupilometers may be used in detecting fatigue in an individual as indicated by the individual's alertness or sleepiness, detecting the presence of alcohol or drugs, or Alzheimer's disease, and detecting other conditions related to nervous system functional impairment. Thus, pupilometers may be useful in the medical, transportation, and military and law enforcement fields, in industry, and in other areas in which it is desirable to detect such conditions. However, pupilometers have meet with limited acceptance, particularly in the transportation, military and law enforcement fields, due in part to certain deficiencies of prior pupilometers.
Briefly, conventional modern pupilometers generally include optical-electronic apparatus for generating a pupillary response-inducing light stimulus, and for measuring the diameter of the stimulated pupil over a period of time to establish the response (including parameters such as pupil constriction velocity, initial, minimum and final pupil diameter, time to minimum, and reflex amplitude) of a user/subject's pupils to the light stimulus. To this end, conventional pupilometers typically include visible light emitting diodes to produce the response-inducing light stimulus (i.e., diodes to generate a visible flash of light directed along an optical path and at the subject's eye to cause contraction of the subject's pupil), and infrared diodes (or other IR source) and associated optics and electronics adapted to direct the IR source to and from the subject's eye for measuring the dynamic pupillary response to the light stimulus. The pupillary response measuring apparatus typically includes either (i) an electronic pupil-imaging device such as a charge-coupled device (CCD) or other optical detector array, the image being detected on a two-dimensional detection device or a one-dimensional scanning device and then processed for pupil size information, or (ii) apparatus for detecting IR light scattered from the subject's eye and converting the detected optical power to an electrical signal indicative of the diameter of the pupil. A target arrangement is typically provided to assist the user in alignment of the pupil to be tested with the optical path of the optical-electronic apparatus. Pupilometers have been provided with apparatus for automatically detecting the presence of a pupil in the optical path of the optical-electronic apparatus, and/or the position of the pupil relative to the optical path, to provide either the user with pupil position feedback or a test administrator or operator with pupil position information indicating proper pupil alignment for test initiation, and/or for tracking the position of the pupil. Provision is also typically made for a microprocessor-based controller to control the operation of the optical-electronics apparatus and to analysis the pupillary response data, and for storage of the response data and analytical results.
Additional specific information regarding pupilometers, and the use of pupillometers and pupillary response data in detecting the presence of conditions related to nervous system impairment is provided in, among others, Scinto et al., U.S. Pat. No. 5,617,872 (Hypersensitive Constriction Velocity Method for Diagnosing Alzheimer's Disease in a Living Human) and U.S. Pat. No. 5,704,369 (Non-Invasive Method for Diagnosing Alzeheimer's Disease in a Patient); Carter, U.S. Pat. No. 5,646,709 (Portable Hand-held Pupillometer with Dynamic Electronic Image Centering Aid and Method of Use Thereof), U.S. Pat. No. 5,661,538 (Portable Self-Measurement Pupillometer with Active Opto-Electronic Centering Aid and Method of Use Thereof), U.S. Pat. No. 4,755,043 (Portable Scanning Digital Pupillometer and Method of Use Thereof) and U.S. Pat. No. 5,187,506 (Method and Apparatus for Determining Physiological Parameters Based on Pupil Response); Gardner et al., U.S. Pat. No. 4,850,691 (Method and Apparatus for Determining Pupillary Response Parameters); Rothberg et al., U.S. Pat. No. 5,422,690 (Fitness Impairment Tester); Cornsweet et al., U.S. Pat. No. 5,410,376 (Eye Tracking Method and Apparatus) and U.S. Pat. No. 5,042,937 (Optical System for an Ophthamological Instrument for Examination of Pupillary Responses); Kardon, U.S. Pat. No. 5,490,098 (Automated System and Method for Determining Pupillary Threshold Response); and Anderson, U.S. patent application No. 09/312,094.
In general, pupilometers are available in table-top models and hand-held models. In order to measure and record pupillary response data, and for analysis of the response data, such prior pupilometers are typically tethered to a laptop computer, or other microprocessor based control and data processing and storage unit with a data and power transmission line.
Table-top model pupilometers are typically of binocular construction for testing both of the subject's eyes. One such prior pupilometer is disclosed in Carter, U.S. Pat. No. 5,661,538. This pupilometer is equipped with a binocular optical block for stimulating the subject's pupils and detecting pupillary response with an electronic imaging device, a selector knob to enable testing of one eye and then the other eye, and may be tethered to a laptop computer for power requirements, for software control processing such as to drive the optical block, and to provide means for analyzing the pupillary response data.
Prior hand-held pupilometers are typically of monocular construction and operation, and are also typically tethered to a laptop computer for instrument control and data processing and storage purposes. Unfortunately, such tethered arrangements are inconvenient if the pupilometer is to be used at a location remote from an office, laboratory or other controlled environment because the operator must carry-along and set-up the computer at the remote location, and because the testing location is limited to proximate the laptop computer by the length of the tether line.
As a result, such prior pupilometer are not practical for extensive "field" use such as would be common in transportation, military and law enforcement fields, and have met with limited acceptance in such fields. In addition, the need for the laptop computer results in substantial additional expense over and above the cost of the pupilometer instrument.
Hand-held pupilometers are disclosed in Carter, U.S. Pat. Nos. 5,646,709 and 4,755,043. Each of these pupilometers are of monocular construction and operation, with an elongated handle for one-handed gripping, and with an enlarged head which carries an eyepiece and the associated light generating and pupillary imaging and response measuring optics. Unfortunately, in addition to being tethered to a laptop computer, a pupilometer with this construction presents the potential to used as a weapon if given to a non-friendly subject for self-testing, such as to a subject to be tested for the presence of alcohol or drugs. Specifically, the "hammer-like" construction of such prior hand-held pupilometers presents a danger that the operator may be struck with the enlarged head if the instrument is swung in an aggressive manner by the user. Such an arrangement has presented an additional barrier to acceptance of prior hand-held pupilometers in law enforcement and related fields.
One prior hand-held pupilometer of Fairville Medical Optics, Inc. of the United Kingdom, identified under the name/trademark PUPILSCAN II, Type 12, is a self-contained, hand-held pupilometer that is adapted to test and record pupillary response data without the need to be tethered to a separate microprocessor-based control and data processing device. However, this pupilometer is of conventional pupilometer monocular construction, having an enlarged head and an elongated handle, and therefore presents the same potential to be used as a weapon as associated with other prior hand-held pupilometers.
Thus, there is a need for a cost-effective, self-contained, hand-held pupilometer that is capable of measuring, analyzing and storing pupillary response data without the need to be tethered to a separate microprocessor-based control and data processing device for ease of field use, and that is constructed to reduce the potential weapon-like nature of the instrument and thus reduce the likelihood that the pupilometer may be used by the test subject as a weapon against an operator administering or observing the test.